Über substituierte Phenalenium-Ionen

Abstract

As predicted by HMO calculations the behaviour of the highly symmetrical phenalenium cation is markedly altered when substituents are introduced at the 1- or 3-position. This is especially true for OR- or NR₂-substituents as well as for substituents derived from various reactive methylene compounds. 

Disubstitution reduces the phenalenium character in favour of a trimethine system condensed to a naphthalene ring. The synthesis of characteristical compounds from 1-alkoxy- or 1,3-dialkoxy-phenalenium cations is reported. Some of these products are reversibly protonated and undergo reversible two-step oxidation forming stable radical ions.